Police withdrew permission for it to take place because of the unrest earlier in the day but reversed their decision after a meeting with the organisers, the G8 Alternatives, an umbrella group representing organisations such as trades unions and churches.

Some left the march at about the halfway point and walked to the security fence which rings the hotel, where US President George Bush, Prime Minister Tony Blair and other G8 leaders have taken up residence until Friday.

The protesters, some carrying banners including slogans such as "justice for all" and "make occupation history" were joined by a group who blew horns and banged drums.

One or two climbed trees close to the security fence. An American flag was thrown to the ground and set on fire.

They moved along the fence and gathered at a temporary police watchtower.

Some of the protesters began throwing missiles, including wooden stakes, at the police, who responded by bringing in dogs and used their shields to charge people backwards.

Helicopter reinforcements

Reinforcements were dropped into the area by Chinook helicopters and at the outer cordon, through which protesters had passed, officers in reflective jackets and caps were replaced by colleagues in riot gear.

By 1725 BST, most of the protesters who had entered the field had been moved back onto the main procession route, although some still stood facing police.

A total of 100 activists engaged in running confrontations outside Auchterarder were arrested.

Police said 29 officers had been injured in the disturbances, with five requiring hospital treatment. None of the injuries was described as serious.

Before the march set out at 1415 BST, Gill Hubbard, of G8 Alternatives, said: "I'm sure all of you will agree that this would have been a travesty of democracy if we were not allowed to protest against the warmongers. "We're on this side of the fence, they're on that side of the fence. Which side are people on?

"Anyone who watched the television pictures of criminal and violent activities in Stirling this morning would understand why we have had to proceed cautiously to ensure this march could go ahead safely."

Marchers proceeded through Auchterarder and most fulfilled their promise of a noisy protest "within earshot" of G8 leaders gathered at Gleneagles. BBC journalists said the atmosphere was "good-natured".

Causing trouble

In Edinburgh, hundreds of protesters said they had been prevented from leaving for Gleneagles.

They organised their own march in the centre of the city and some expressed bitterness that they had not been allowed into Auchterarder.

Lothian and Borders Police made 17 arrests during the day.

The man in charge of Scotland's G8 police co-ordination centre said the time for playing "softball" with people intent on causing trouble was now over.

People on the march before a group broke away for the fence

Chief constable Peter Wilson said those involved in trouble had shown no interest in the rule of law.

Trouble flared in the early hours after people began moving from an eco-campsite near Stirling towards the Gleneagles area. Some protesters were escorted back to the site by police in riot gear.

The centre of Stirling was closed, as was the M9 at the Granada services after it was blocked by protesters. Police arrested 32 people there.

Vehicles, banks and a Burger King restaurant on the Springkerse retail park in Stirling were attacked.

Rail services were also disrupted for a time, with a confrontation between police and protesters at Stirling and a temporary blockade of the rail line north of Dunblane.

Twenty police officers suffered minor injuries in confrontations.

Scotland's First Minister Jack McConnell condemned the violence and accusing those involved of drawing attention away from important issues due to be discussed at the summit.